Some specimens are more equal than others

I got into a discussion with my colleagues the other day about the merits of collecting multiple specimens of taxa versus collecting something new. The reality of course is that there is rarely a choice to be made – you bring back everything you find in the field that you can. However, as a hypothetical discussion it is interesting since of course you can do very different science with 10 specimens representing 10 different species and 10 specimens of a single species.

This debate aside (one for another time) it led me to get around to writing this post which I have long intended to complete on the differing importance of different specimens. It is understandable that some people might think “so you have 25 Triceratops, so what? Surely once you have one good, complete one, there’s not much more to learn?” but of course this is far from the truth.

As I have covered before on my series of posts on taxonomy, multiple specimens can give you a huge insight into the variation of fossil animals as living organisms – be it intraspecific or sexual. If animals are of different ages then you can learn about ontogeny and growth and of course there is always the change that a new specimen shows off some odd characteristic like a pathology, bite marks from a predator or something like this.

Some specimens (and the fighting dinosaurs are a great example) cannot easily be prepared for research, no matter how good they are (or in this case, not without losing a lot of other important information). Another specimen where all the bones can be separated out and viewed and analysed in 3D is great therefore allowing all kinds of extra information to be accessed and things like range of motion in joints to be examined firsthand. Similarly, having a ‘sacrificial’ specimen is great – no one wants to chop up a brilliant holotype to look at the bone histology or look at replacement teeth or the braincase, but a second specimen allows you to be a bit free-er with your methods and destructive sampling becomes a serious option – even a very fragmentary partial bone can be enough for this.

OK, maybe we don't need to collect this.

So while obviously for most palaeontologists a single complete skeleton is a great find, every little specimen is valuable. However, it would be a mistake to consider each of equal value – a single broken femur is good for destructive sampling, but an articulated leg is more useful and obviously several complete animals are better still. Even this varies from researcher to researcher – histologists are likely overjoyed by a bunch of otherwise largely unimportant partial specimens that they can sample while behaviourists won’t get too worked up until they hit a whole herd preserved together.

I imagine most of this is largely very obvious, but still there is typically always one more angle to think about and I hope I may have highlighted one or two here. It’s easy to get stuck in the mindset of ‘what would I do with that fossil’ which might be very useful for you, but not always that of your colleagues.